This invention relates to thermal protection systems for re-entry or hypersonic vehicles and more particularly relates to a method and system for assembly and attachment of high temperature materials.
Since the onset of space exploration, thermal protection systems (TPS) have played a key role in enabling vehicular travel to and from space. Thermal protection systems are comprised of a variety of materials and configurations with the purposes of protecting a vehicle, structure and/or instrumentation from the thermal and environment effects of rapidly re-entering earth""s atmosphere. During the course of any one mission, a vehicle is exposed to launch conditions, micrometeorite impacts, extreme temperatures in rarified atmospheric conditions and runway debris, all of which can cause damage to the TPS. To this effect, it is highly desirable to have a protection system maintainable with low operating cost.
An example of a currently used and experienced thermal protection system is seen on the Space Shuttle Orbiter. This vehicle utilizes numerous materials to protect it from the harsh re-entry environment. The windward acreage of the Shuttle is covered with tiles made of rigid ceramic foam. These tiles are termed alumina enhanced thermal barrier (AETB) tiles and are bonded to the vehicle""s aluminum sub-structure and thereby provide a smooth aerodynamic surface and a thermal barrier. The leeward acreage is also protected from the re-entry environment, albeit an environment less severe than windward, with ceramic insulation in the form of blankets that are also bonded to the outer surface of the vehicle. Each of these types of insulation are considered parasitic in that they are bonded to the vehicle to provide thermal protection but do not substantively add to its structural integrity because they do not posses adequate structural strength. In the case of the tile applications, each piece is custom fit to exacting specifications and attached to the vehicle with an elaborate bonding procedure. When a tile is damaged, the individual tile is removed and the process must be repeated and inspected to assure that the replacement tile, when installed, meets the vehicle""s requirements. This replacement and inspection process is very time consuming and is a costly part of the operation of the Space Shuttle Orbiter.
The Space Shuttle Orbiter also utilizes load-carrying thermal protection in the form of carbon/carbon (C/C) composites that can be found on the nose cap of the vehicle. This material differs from the aforementioned TPS in that it is a fiber reinforced composite material that is better suited to accommodating structural loading. Typically, the backside of each C/C component is insulated and then each C/C component is attached to the vehicle""s substructure via bolts, or some other suitable method, that is generally inaccessible from outside the vehicle.
There is a need for new method and system for attaching thermal barrier panels subject to re-entry environments to underlying vehicle surfaces with the panels exhibiting having improved structural properties over tile and blanket applications.
The method and system of attachment and assembly applies self-fixturing using integral tenons and mortises and other composite manufacturing methods to high temperature structures. The method and system of attachment permits efficient attachment of a TPS panel to the substructure or fuel tank of the vehicle using TPS panel fittings, flexure fittings, and fasteners. The present invention allows the TPS panel to be installable, removable and replaceable via fastener access from the exterior of the vehicle provided by access cover plates. Additionally, the present invention enables the user to rapidly service the vehicle for low cost, quick turnaround similar to commercial aircraft-like operations.